Sheet folding machines have long been well known and have enjoyed great commercial success in a variety of document processing applications, particularly those associated with the preparation of mail in which one or a plurality of sheets are folded in a variety of configurations before being inserted into envelopes in an envelope inserting machine. Briefly, folding machines of this character comprise one or a pair of buckle chutes and a plurality of sets of feeding and folding rollers. In a typical arrangement, sheets are fed into the folding mechanism and directed into a first buckle chute by a first pair of feeding rollers until the lead edge of the sheet strikes a stop, after which the portion of the sheet adjacent to the entrance of the buckle chute buckles to form a new lead edge, which then passes through the next pair of feeding rollers which creases the new lead edge, thereby forming a first fold in the sheet. The new lead edge is then directed into a second buckle chute until it strikes a stop, which causes the portion of the sheet adjacent to the entrance of the second buckle chute to buckle and form still another new lead edge, and this new lead edge then passes through still another pair of feeding rollers which again creases the lead edge, thereby forming a second fold in the sheet. The tri-folded sheet is then fed through a discharge path from the folding machine.
Typically, inserter systems prepare mail pieces by gathering collations of documents on a conveyor. The collations are then transported on the conveyor to an insertion station where they are automatically stuffed into envelopes. After being stuffed with the collations, the envelopes are removed from the insertion station for further processing. Such further processing may include automated closing and sealing the envelope flap, weighing the envelope, applying postage to the envelope, and finally sorting and stacking the envelopes.
Often times the address of the recipient appears on the folded insert, which is then inserted into a windowed envelope. Sometimes the recipient's address appears on the top ⅓ panel of the document. In these cases the conventional two buckle chute folder may be configured to fold the document in a “C” or “Z” fold so that the recipient's address will appear through the window of the envelope. The above fold types accommodate the customer needs of certain users. The recipient's address may also appear on different portions of the folded insert, for instance, the bottom portion or middle portion of the folded insert. Bottom addressing and middle addressing of inserts normally require folders with opposite buckle chute arrangements, positioned both above and below the folder paper path. Such arrangements normally results in a folder with a minimum of three buckle chutes to accomplish all the basic fold types, i.e., top address C-fold, and the auxiliary fold types, middle address C fold and bottom address Z fold.
A disadvantage of the prior art is that three buckle chutes are required to perform the basic fold types for bottom and middle addressing of inserts. Another disadvantage of the prior art is that one of the three buckle chutes must be positioned to oppose the other two buckle chutes, making it difficult to transport material past the folder either above or below without folding the material or intersecting the mechanical assembly of the buckle chute.